1. Field of the Invention
The present invention relates to a coordinate detection system, an information processing apparatus, and a recording medium.
2. Description of the Related Art
A system in which an optical information input device is disposed on a board surface of an electronic whiteboard device and handwritten information depicted on the board surface by a user is input in real time to a computer such as a personal computer via the optical information input device is known.
For example, Japanese Laid-Open Patent Publication No. 2004-038528 discloses an optical coordinate detection device including a large-sized coordinate detection plane (display). This coordinate detection device is equipped with a position indicator (a pen-shaped instrument) having light emission points. In this position indicator (electronic pen), two light emission points are provided on a grip part of the position indicator, and a position of the tip of the position indicator is computed based on positions of the light emission points detected by optical sensors.
However, in the above-described coordinate detection device, the impact of mirror-reflection characteristics of a board surface of the display on the computation results is not taken into consideration. In a case where the image quality deteriorates (e.g., when two images of the light emission points overlap each other), the computation of the position of the tip of the position indicator is prone to having a significant error. Hence, the above-described coordinate detection device has a problem that the detection of coordinates of the tip of the position indicator in such a case may be inaccurate.